Cyclohexanone Plant Retrofit via Phenol Hydrogenation
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Solution Overview
Problem
Chemical plants for cyclohexanone production face challenges in increasing capacity beyond their maximum design, as existing methods for oxidation of cyclohexane are energy-intensive, produce significant by-products, and pose safety risks due to explosive cyclohexane-oxygen mixtures, making expansion costly and hazardous.
Innovation Solution
A process is developed to convert existing cyclohexanone production plants from oxidation of cyclohexane to hydrogenation of phenol, involving the retrofitting of plants by disabling cyclohexane oxidation units and adding phenol hydrogenation units, utilizing existing distillation and dehydrogenation equipment, which reduces energy consumption and by-product production while eliminating safety hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the capacity of an existing cyclohexanone production plant is increased by building a new plant or substantially copying the existing one, then the production capacity is improved, but the cost increases significantly
Solution Approach 1:
The existing distillation and dehydrogenation equipment is made multi-functional by adapting it to process phenol hydrogenation products instead of cyclohexane oxidation products. The distillation columns and dehydrogenation units originally designed for cyclohexanone/cyclohexanol separation are reused for the new phenol-based process, eliminating the need to build entirely new production lines and significantly reducing expansion costs.
Solution Approach 2:
The process parameters and chemical reactions are changed from cyclohexane oxidation to phenol hydrogenation. By changing the feedstock and reaction pathway while maintaining the same core separation and purification equipment, the plant achieves increased capacity without proportionally increasing infrastructure costs.
2Productivity
If the existing plant is modified by increasing capacity of rate-limiting components through replacement or duplication, then the productivity is improved, but the device complexity and cost increase
Solution Approach 1:
Instead of replacing or duplicating complex rate-limiting components, the invention makes the existing components universal by adapting them to a new chemical process. The same distillation columns and dehydrogenation units handle different feed compositions and reaction products, avoiding the complexity of designing and installing additional specialized equipment.
Solution Approach 2:
Rather than modifying existing equipment to handle increased loads of the same process, the invention inverts the approach by changing the chemical process itself (from oxidation to hydrogenation) while keeping the equipment configuration relatively simple and unchanged.
3Productivity
If cyclohexane oxidation is used to produce cyclohexanone, then the production process is established, but energy consumption increases and by-products are generated
Solution Approach 1:
The chemical reaction pathway is fundamentally changed from oxidative process to reductive hydrogenation process. Phenol hydrogenation consumes less energy and produces fewer by-products compared to cyclohexane oxidation, while still achieving the same product output. The process parameters including temperature, pressure, and catalyst systems are optimized for the hydrogenation reaction.
Solution Approach 2:
The invention converts the harmful by-products and high energy consumption of cyclohexane oxidation into benefits by using phenol hydrogenation, which inherently produces fewer by-products and lower energy requirements. The unused or modified equipment from the old process is repurposed for the more efficient new process.
4Productivity
If cyclohexane oxidation is used for cyclohexanone production, then the production process is established, but safety risks arise due to explosive cyclohexane-oxygen mixtures
Solution Approach 1:
The chemical process is changed from oxidation (requiring oxygen and creating explosive mixtures) to hydrogenation (using hydrogen with controlled reactions). This fundamental parameter change eliminates the formation of explosive cyclohexane-oxygen mixtures while maintaining productive cyclohexanone output through phenol conversion.
Solution Approach 2:
The harmful safety aspect of cyclohexane oxidation is converted into a benefit by replacing it with phenol hydrogenation, which operates without explosive mixture formation. The existing plant infrastructure is repurposed to support this safer process while maintaining or increasing production capacity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases cyclohexanone production capacity by 10-30% while reducing energy consumption and by-product generation, and eliminates safety risks associated with cyclohexane-oxygen mixtures, providing a more efficient and safer operation.
Implementation Method 1
catalytic reduction of phenol with hydrogen, for example using a palladium-comprising catalyst
Implementation Method 2
Separation of cyclohexanone from this mixture may be made by distillation
Implementation Method 3
Cyclohexanol may also be recovered by distillation and optionally converted to cyclohexanone by dehydrogenation
Data Source
AI summary
A process for the construction of a second chemical plant, which second chemical plant is suitable for the separation of cyclohexanone from a second mixture, which second mixture comprises reaction products from the hydrogenation of phenol. The process comprises providing a first chemical plant, which first chemical plant is suitable for the separation of cyclohexanone from a first mixture, and a second chemical plant comprising a distillation column suitable for distilling overhead cyclohexanone reused from the first chemical plant.